The use of alkali-metal-beta-alumina as an electrolyte for sodium sulfur batteries and alkali-metal halide batteries is known. In addition, alkali-metal-beta-alumina electrolytes are known to be conductive to sodium ions and used in sodium sulfur batteries with liquid sodium as the anode, sulfur or sodium polysulfide as the cathode, and an alkali-metal-beta-alumina electrolyte separating the anode from the cathode. Furthermore, it is known that the operating temperature for such sodium sulfur batteries is typically selected to be between 300-350° C. and such batteries can achieve several thousand charge/discharge cycles.
Regarding alkali-metal halide batteries, a liquid anode of metallic sodium and a solid cathode of porous nickel chloride impregnated with sodium tetrachloro aluminate are known to be used. Similar to the sodium sulfur batteries, the anode and the cathode are separated by an alkali-metal-beta-alumina electrolyte.
Such batteries as discussed above are used in transportation, e.g. electric vehicles, locomotives, etc., as well as in stationary energy storage applications. However, current processes for making the alkali-metal-beta-alumina electrolyte require a sintering process that is time consuming, cost intensive, and thus result in the production of the electrolyte being the largest single cost for the manufacture of sodium sulfur electrochemical cells. In addition, such processing to produce alkali-metal-beta-alumina electrolyte components results in a large grain size for the material which corresponds to low mechanical strength and the presence of the sinter-formed NaAlO2 phase along the grain boundaries making the material susceptible to moisture. Other problems known to exist for current state of the art alkali-metal-beta-alumina electrolyte components for sodium sulfur batteries and alkali-metal halide batteries include rigidity of the electrolyte, large electrolyte thickness which results in a low power-to-energy ratio and high internal resistance, high operating temperatures, and the like. Therefore, an improved process for manufacturing an electrolyte for a sodium sulfur battery and/or an alkali-metal halide battery would be desirable.